Cryptology ePrint Archive: Report 2003/093

Simple Stateless Steganography

Leonid Reyzin and Scott Russell

Abstract: We put forward the first secret-key steganographic construction that is
both black-box (i.e., the sender need not have knowledge of the
channel beyond the ability to sample from it) and stateless (i.e.,
the sender and the recipient need not maintain synchronized state when
sending multiple bits). Both of these properties are important: the first
because in many settings it is unrealistic to assume detailed knowledge of
the underlying channel distribution, and the second because maintaining
synchronized state between the sender and the recipient is particularly
problematic in steganography, where communication to resynchronize will
alert the adversary.

For channels of sufficient entropy, our construction is more efficient than
previous black-box constructions. Moreover, it is the first one to
provide a
tradeoff between the number of samples the encoder needs and the rate at
which hiddentext is transmitted.